Radiation dose estimation of pediatric upper extremity radiographs

Upper extremity radiographic exams have long been considered as a single category with one simplified low-dose estimate, despite covering a variety of body parts. There are limited tools currently available for the simulation/calculation of radiation dose from upper extremity exams.

This study aims to evaluate radiation dose (in terms of effective dose and organ doses) from various types of pediatric upper extremity radiographic exams as performed at a large tertiary care children's hospital using a new set of hybrid computational phantoms that incorporate the anatomy of upper extremities and cover varied patient sexes and ages.

Technical acquisition parameters were collected for upper extremity exams at our institution according to the age-based categories as defined by clinical protocols. A relationship was established between radiographic acquisition parameters and dose-area product for each category using direct measurements. A new set of computational phantoms with posed upper extremities was introduced and used to run Monte Carlo simulations of patient effective dose and organ doses for all relevant projections.

The calculated effective dose to upper extremities was found to range from 0.01 µSv for a hand/finger radiograph of a 3-6-year-old to 1.13 µSv for a humerus radiograph of a 1-3-year-old. The four tissues with the highest organ dose from all projections were the same: skin, muscle, endosteum, and red marrow. Doses to these organs as well as breast and thyroid were reported, and conversion coefficients to estimate effective dose and organ doses from dose-area product were calculated.

Simulations of pediatric upper extremity radiographs using a set of newly-modified computational phantoms present a wide range of effective and organ doses. The doses reported in this study can be adapted to site-specific practices for rough estimations.